wifi connection email question

I would welcome any help. I will try and be as clear as possible and I hope I posted on the right board.

1. I connect my macbook air to email via wifi at home.
2. When I do this I can send and receive emails using the mac email program
3. I can also connect to the internet as well.

Now the problem

1. When I am in a hotel say and connecting to the internet using a wifi hotspot:-
2. I can surf the internet with no issues
3. But cannot seem to send or receive any emails.

I also have a similar problem with my iphone except even at home I can't send any emails when wifi is on but it receives with no issues. Again, using a wifi hotspot I have the same issue. Turning off wifi and switching to 3g or edge I can receive and send emails.

Roaming can be a bit tricky as some outfits with WiFi tend to close posts for various reasons. If your email is set up thru port 25 then that may be closed off to try and reduce spam at Hotspot. Try port 587. You may find the Air works more reliably if you set up a Location for home and leave Automatic for hotspots